Learn why a drives stated label capacity is not the same as the capacity shown by Windows or macOS operating systems.*END
Systems will use both decimal and binary to measure the size.
A drive's size is measured by using the total number of bytes that can be used on the drive.
Find Out Decimal Capacity
Take the total number of bytes on the drive and divide it per gigabyte (1,000,000,000 using base 10).
A decimal (base 10) of bytes is:
- Megabyte = 1,000,000 bytes
- Gigabyte = 1,000,000,000 bytes
- Terabyte = 1,000,000,000,000 bytes
Find Out Binary Capacity
Take the total number of bytes on the drive and divide it per gigabyte (1,073,741,824 using base 2).
A binary (base 2) of bytes is:
- Megabyte = 1,048,576 bytes
- Gigabyte = 1,073,741,824 bytes
- Terabyte = 1,099,511,627,776 bytes
This is why some systems will report different sizes for the same drive.
The drive's full space available for storage can be used.
Drive Sizes, Binary and Decimal Capacities
| Drive Size | Approximate Total Bytes | Decimal Capacity (bytes/1,000,000,000) (Usual Displayed Capacity On macOS) |
Approximate Binary Capacity (bytes/1,073,724,841) (Usual Displayed Capacity On Windows and Linux) |
| 10 GB | 10,000,000,000 | 10 GB | 9.31 GB |
| 20 GB | 20,000,000,000 | 20 GB | 18.63 GB |
| 30 GB | 30,000,000,000 | 30 GB | 27.94 GB |
| 36 GB | 36,000,000,000 | 36 GB | 33.53 GB |
| 40 GB | 40,000,000,000 | 40 GB | 37.25 GB |
| 60 GB | 60,000,000,000 | 60 GB | 55.88 GB |
| 74 GB | 74,000,000,000 | 74 GB | 68.91 GB |
| 80 GB | 80,000,000,000 | 80 GB | 74.51 GB |
| 100 GB | 100,000,000,000 | 100 GB | 93.13 GB |
| 120 GB | 120,000,000,000 | 120 GB | 111.76 GB |
| 150 GB | 150,000,000,000 | 150 GB | 139.69 GB |
| 160 GB | 160,000,000,000 | 160 GB | 149.01 GB |
| 180 GB | 180,000,000,000 | 180 GB | 167.64 GB |
| 200 GB | 200,000,000,000 | 200 GB | 186.26 GB |
| 250 GB | 250,000,000,000 | 250 GB | 232.83 GB |
| 300 GB | 300,000,000,000 | 300 GB | 279.40 GB |
| 320 GB | 320,000,000,000 | 320 GB | 298.02 GB |
| 400 GB | 400,000,000,000 | 400 GB | 372.52 GB |
| 500 GB | 500,000,000,000 | 500 GB | 465.65 GB |
| 640 GB | 640,000,000,000 | 640 GB | 595.84 GB |
| 750 GB | 750,000,000,000 | 750 GB | 698.47 GB |
| 1 TB (1000 GB) | 1,000,000,000,000 | 1 TB (1000 GB) | 931.30 GB |
| 1.5 TB (1500 GB) | 1,500,000,000,000 | 1.5 TB (1500 GB) | 1396.95 GB |
| 2 TB (2000 GB) | 2,000,000,000,000 | 2 TB (2000 GB) | 1862.6 GB |
| 3 TB (3000 GB) | 3,000,000,000,000 | 3 TB (3000 GB) | 2793.97 GB |
| 4 TB (4000 GB) | 4,000,000,000,000 | 4 TB (4000 GB) | 3725.29 GB |
| 5 TB (5000 GB) | 5,000,000,000,000 | 5 TB (5000 GB) | 4657.49 GB |
| 6 TB (6000 GB) | 6,000,000,000,000 | 6 TB (6000 GB) | 5587.94 GB |
| 7 TB (7000 GB) | 7,000,000,000,000 | 7 TB (7000 GB) | 6519.36 GB |
| 8 TB (8000 GB) | 8,000,000,000,000 | 8 TB (8000 GB) | 7450.58 GB |
| 10 TB (10000 GB) | 10,000,000,000,000 | 10 TB (10000 GB) | 9613.37 GB |
| 12 TB (12000 GB) | 12,000,000,000,000 | 12 TB (12000 GB) | 11176.04 GB |
| 14 TB (14000 GB) | 14,000,000,000,000 | 14 TB (14000 GB) | 13038.72 GB |
| 16 TB (16000 GB) | 16,000,000,000,000 | 16 TB (16000 GB) | 14901.39 GB |
| 18 TB (18000 GB) | 18,000,000,000,000 | 18 TB (18000 GB) | 16763.81 GB |
| 20 TB (20000 GB) | 20,000,000,000,000 | 20 TB (20000 GB) | 18626.74 GB |
| 24 TB (24000 GB) | 24,000,000,000,000 | 24 TB (24000 GB) | 22352.09 GB |
| 28 TB (28000 GB) | 28,000,000,000,000 | 28 TB (28000 GB) | 26077.44 GB |
| 32 TB (32000 GB) | 32,000,000,000,000 | 32 TB (32000 GB) | 29802.79 GB |
| 40 TB (40000 GB) | 40,000,000,000,000 | 40 TB (40000 GB) | 37253.49 GB |
| 50 TB (50000 GB) | 50,000,000,000,000 | 50 TB (50000 GB) | 46566.86 GB |
| 75 TB (75000 GB) | 75,000,000,000,000 | 75 TB (75000 GB) | 69850.29 GB |
| 100 TB (100000 GB) | 100,000,000,000,000 | 100 TB (100000 GB) | 93133.73 GB |
